As a high-performance permanent magnet, rare earth magnets such as Sm—Co based magnets and Nd—Fe—B based magnets are known. When permanent magnets are used in motors for hybrid vehicles (HEV) and electric vehicles (EV), heat resistance of permanent magnets is demanded. In motors for HEV and EV, there are used permanent magnets whose heat resistance is increased by replacing a part of Nd in the Nd—Fe—B based magnets with Dy. Since Dy is one of rare elements, permanent magnets not using Dy are desired. As a motor and a generator with high efficiency, a variable magnetic flux motor and a variable magnetic flux generator using a variable magnet and a stationary magnet, are known. In order to achieve high performance and high efficiency of the variable magnetic flux motor and the variable magnetic flux generator, increase in coercive force and magnetic flux density of the variable magnet and the stationary magnet is demanded.
The Sm—Co based magnets have high Curie temperature, and thus they are known that they exhibit excellent heat resistance without using Dy, and they can realize good motor characteristics at a high temperature. Among the Sm—Co based magnets, Sm2Co17 type magnets can also be used as variable magnets based on a coercive force exertion mechanism thereof. The Sm—Co based magnets are also required to increase coercive force and magnetic flux density. For realization of high magnetic flux density of the Sm—Co based magnets, increase in Fe concentration is effective, but the coercive force tends to decrease in a composition region having high Fe concentration. Therefore, there is desired a technique to allow exertion of large coercive force in Sm—Co based magnets with high Fe concentration.